Anticonvulsant blood levels (ABLs) and area-under-the-concentration-time-curves (AUCs) will be used as direct measures of drug exposure. The results will enable clinicians to prospectively calculate individual dosing regimens for the mother in order to optimize dosing and limit unnecessary drug exposure to the child. In addition, genetic samples will be collected, which will provide a valuable resource for future pharmacogenetics studies to further delineate individual variability across patients.